Transcript Software

Software
The set of instructions which are used to perform specific task
is called software.
Or
The set of instructions that tells the computer what to do is
called software.
Examples
● Microsoft word
● Microsoft excel
● Windows xp etc.
Hardware
Physical parts of the computer is called hardware. These are
seen able and touch able.
Examples
● Key board
● Mouse
● Printer
● Mother board
● Hard disk etc.
Relationship between hardware &
software
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In order to produce useful output the hard ware and soft
ware must work together.
● Both are complementary to each other.
● No useful can be obtained its own with out hard ware if
soft ware is not used.
● Example is a cassette player.
● And remember that hardware is necessary but soft ware is
vital.
● Soft ware production is difficult and expensive.
● Hard ware is a one time investment.
Types Of Software
Computer software is normally classified into four broad
categories.
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Application software
Custom made software
System software
Programming and Translation software
Application Software
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Computer soft ware that written for some particular
application is called computer application software.
● Application software are also called general purpose or
“off- the- shelf” package.
● They provide solution to a range of different problems
related to a particular type of application.
Examples
● Word processing
● Spread sheets
● Database management system
● Presentation designers
Drawbacks Of Application Software
1- Bloat ware (Too many features)
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Some soft ware has become so crowded or bloated with
feature that it has led to the term bloat ware
The reason to introduce to so many feature is that the
customer rush to buy new one to remove his old one.
Example
When micro soft office came on the market supplanting
office 97, it contained more than 6000 commands, far more
than the few dozen or even few hundred that most people
would use.
2- Shovel ware (Full of flaws)
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Soft ware makers are in such a hurry to ship or shovel their
products out the door to the market that it has inspired a
new word” shovel ware” and a lot of shovel ware are
developed so hastily that it doesn’t work right
Sometimes an applications program doesn’t perform
because of incompatible standard with other parts of the
computer system
For instant it is not compatible with newer or older version
of operating System
Custom Made Software
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Custom made soft ware are also called special purpose
“bespoke” software.
These soft ware are written to meet the processing needs of
an individual or an organization.
These software's are prepared for the computing need of a
company when required soft ware is not available in the
market.
Creating a software is the responsibilities of “MIS”
department.
In house changing are also made when commercial soft
ware requires extensive reprogramming
Custom made soft ware are prepared when company
required security and that security can not made by
commercial packages
Examples are payroll, inventory, accounts, sales,
production, marketing.
System Software
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System software is a set of one or more programs,
designed to control the operation of a computer system.
● System soft ware controls the hard ware
● Application software can be able to run through system soft
ware
● They are general programs written to assist humans in the
use of computer system.
● System soft ware communicate with peripheral devices
(hard ware).
● the program include in system soft ware are called system
programs and a person who prepare system soft ware is
called system programmer.
● Good systems software allows application packages to be
run on the computer with less time and effort.
● A computer would be very ineffective and most likely
impossible to operate.
Types Of System Software
1- Operating System
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Operating system is a collection of control, processing, and
data management programs specially designed to manage
the resources of computer system.
OS is also be defined as the Resource Manager
Modern computer system are so fast that they need internal
control
The complexity of system demand that jobs are controlled in
what they are allowed to do for the sake of security although
over all user is provided with greater flexibility.
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Leading operating systems for PC
a)
DOS (Disk Operating System)
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DOS was most popular operating system for
16 bit Pc’s.
It is used with older PCs based on the “IBM”
PC standard because so much application soft
ware are written for system using Dos.
DOS does not support multitasking and limits
The size of the program in memory to 640K.
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b) Windows
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Microsoft windows 3.x is an operating environment that
lays a graphical user interface shell around the Dos
operating system and extended Dos capabilities.
Different version of windows are (3.0,3.1,3.11 for work
group)
Windows support limited forms of multitasking and
networking but share the memory limitation of Dos.
Early windows has some problem with application
crashes
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Microsoft windows 98 and windows 95 are genuine 32 bit
operating systems.
● A 32 bit operating system can run faster than DOS, which
could only address data in 16 bit chunks.
● Windows 98 and windows 95 provide graphical user
interface (GUI).
● Windows can perform multitasking and multithreading (the
ability
to
manage
multiple
independent
task
simultaneously).
● Windows 98 also provide the capabilities of networking.
● Windows 98 is more effect with internet as compare to
windows 95.
● It support the function of DVD, video conferencing,
cameras, scanners, TV tuner adapter cards and joy stick.
● It integrate with web browser soft ware.
● It gives the facilities to view hard disk and web browsing.
c) Windows NT:
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Windows NT is another 32 bit operating system
It supported large networks.
Windows NT is a multitasking, multi user,
multiprocessing network operating system with graphical
user interface.
Windows NT support programs written for Dos and
windows
It can support multiprocessing with multiple CPUs
There are two version of Windows NT workstation and
Windows NT Server.
d) Windows CE:
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Windows compact edition(CE) has some of the capabilities
of windows including its graphical user interface.
It is used in small hand held computer, personal digital
assistance or wireless communication devices such as
pagers and cellular phones.
It requires very little memory.
Non pc devices use this operating system to share
information with windows based PCs and to connect to the
internet.
e) OS/2:
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OS/2 is designed to run on many recent IBM and IBM
compatible microcomputers.
OS/2 is a 32 bit operating system for powerful IBM
compatible PCs with intel microprocessors.
OS/2 is used at where complex , memory intensive
application are required or where networking or
multitasking are require.
OS/2 support applications that runs under windows and
Dos and has its own graphical interface.
It has two version OS/2 warp and OS/2 warp server.
OS/2 warp is for personal users
OS/2 warp server has ability like windows NT for
supporting networking.
f) UNIX
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It is a multitasking operating system for multiple users that
has built in networking capabilities and version that can
run on all kind of computer.
● Unix is an interactive, multi- user, multitasking operating
system developed by Bell Laboratories in 1969 to help
scientific researchers share data.
● Unix is highly supported to networking.
● Unix is design for mini computers but now has version for
PCs , work stations and server computers.
● It can store large number of files.
● Unix is powerful but very complex, with bulk of
commands.
● Graphical user interface has developed for Unix.
● Unix also generate some security problems because
multiple jobs and users can access the same file
simultaneously.
g) MAC OS
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Mac OS the operating system for the Macintosh
computer has features of multi tasking as well as
powerful multimedia and networking capabilities and a
mouse driven graphical user interface.
The Macintosh operating system runs only on Apple
Macintosh computers or on Mac clones.
Apple kept Macintosh price high and refused to license
any clones, Mac are expensive
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Functions of operating system
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Helps in booting up process of the computer.
Checking that the hard ware is functioning properly.
Defines user interfaces.
Scheduling and loading of jobs in order to provide
continuous processing.
Control of user selection and operation of input/out put
devices and file handling.
Calling into main storage of programs and subroutines as
and when required.
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Opening and closing file and checking of file label.
● Maintenance of directories in external storages.
● Passing of control from one program to another program
when more than one application is open.
● Communication with computer user by means of input and
output devices.
● Managing tasks such as multi tasking, multiprogramming,
multi processing and timesharing.
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Characteristics of operating system
a)
Single User
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The stand alone environment refer to as single user.
One person can communicate one computer only.
The is no net work environment
b)
Multi User
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Multi user mean many geographically processing system
are connected by telecommunications network and in
which messages processing tasks, programs data and
other resources between terminals
Benefit is that sharing of resources in term of hard ware
and software.
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c) Multi-Programming
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Multiprogramming permits the running of several
programs in sequence
Multi programming is a basic form of parallel processing
in which several programs are run at the same time on a
single processor
There is only one processor, there can be no true
simultaneous execution of different programs
The real power is operating system that executive part of
one program, then part of another and so on
But some times a computer is so overload that its delays
the shared nature of the machine more obvious
d)
Preemptive Multiprogramming
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Preemptive multi programming is a task in which a
computer operating system uses some criteria to decide
how long to allocate to any one task before giving
another task a turn to use operating system
The act of taking control of the operating system from
one task and giving it to another task is called
preempting (block, chunk, slab)
The common criterion for preempting is simply elapsed
time or time slicing
In some operating systems some applications can be
given higher priority than other applications
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Time Sharing:
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Use of computer by many users each having its own
input and out put devices and accessibility to the
computer at the same time
The computer in such cases gives each user a small but
frequently repeated slice of time
That’s why each user gets the immediate response.
This kind of multi programming is called time sharing
f)
Multi Tasking
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Computer hardware (processor) and soft ware that
permits more than one programs to run at the same time
Multitasking required multi processor
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g)
Multi Tasking
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d
Programming & Translation Software
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Language
A language is defined as a system of communication.
● A discipline that conveys ideas or emotions to one another.
● Every language consist of symbols, characters and usage
rules that permit people to communicate with the
computer.
● With the help of computer language a programmer tells
computer what to do.
● Writing instruction is called coding
Types Of Languages
There are two types of language.
 Low Level Languages
 Machine Language
 Assembly Language
 High Level Languages
 Basic
 Fortran
 Cobol
 C
 C++
 Visual basic
 Java
1- Machine Language
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Machine language is the basic language of the computer
representing data as (1’s or o’s) which the computer can
run directly.
It does not need further translation before being executed.
This is the fundamental language of the computer because
computer can only understand this language.
Basic instruction consist of two part.
First part consist of operation code what is to be do.
Second part consist of memory location address
Machine language provides economy of instruction but
they are inconvenient to the user.
Machine language required through knowledge of
compute hard ware.
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Advantages
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Program written in machine language can be executed very
fast by the computer
Because machine instructions are directly understood by
CPU and no translation of program is required
Machine language written in binary numbers( 1 and o) and
that is the language of computer.
Program written in machine language is no need to further
translate
Less Instruction are required because computer understand
it
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Disadvantages
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Computer internal structure are different from another type
of computer so problem arise.
Machine language is difficult to program because either
programmer has to learn dozen’ of command or use
reference card.
Also expert programmer is required who knows about hard
ware structure of the computer.
It is difficult to correct or modify machine language
programs.
Checking of machine language program is as difficult
write initially.
Machine language is machine dependent.
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Programmer must know the logical structure of the
computer in order to write a good machine language
program.
● Writing programs in machine language required expert
level of programmer and effort.
● The result of all these produce high cost.
● All phases of programming like coding, debugging, testing
is high in machine language.
2- Assembly language
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Assembly language allows a computer user to write
program using abbreviation or more easily remembered
word instead of binary numbers
To ease programmer burdens symbols were developed
The assembly language is machine dependent
Program written in assembly language is converted into
machine language with assembler
There is a one-to-one correspondence between the
assembly instruction of source program and the machine
instructions of object program
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Translation Software
There are three types of translator
(i) Assembler
(ii) Compilers
(iii) Interpreters
1- Assembler
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A language that’s use letters and symbols in place of number
is called assembly language.
The translator software that convert assembly language to
machine code is called assembler.
The assembler is a system program that is provide the
computer manufacturer
It is prepare by system programmers with great care.
2- Compilers
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Since computer hard ware is capable of understanding only
machine level instructions so there must be a soft ware that
convert this high level language into machine level
language.
● So compiler is a software that convert high level language
into machine language.
● Program written in high level language is called source
code.
● When source code is convert to machine code through
compiler is called object code.
● This software compile the whole program at once.
3- Interpreters
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Interpreters is another soft ware that convert high level
language into machine language.
It takes one statement of high level language and convert
them into machine language.
Translation and execution alternate for each statement
encountered in the high level language program.
Interpreters translates one instruction and control unit
executes the resulting machine code the next instruction is
translated and control unit executes the machine code
instruction and so on.
Outsourcing
Outsourcing refers to organizations buying in services and
expertise rather than employing their own staff to perform
functions.
Outsourcing practices relate to contractual agreements
under which an organization hands over control of part, or
all, of the functions of the Information System department
to an external party.
The contractor provides the resources and expertise
required to perform the agreed service, outsourcing is
becoming increasingly important in many organizations.
The specific objectives for IT outsourcing vary form
organization to organization.
Types of outsourcing
Classification
Comments
Ad-hoc
The organization has a short-term requirement for
increased IS/IT skills. An example would be employing
programmers on a short-term contract to help with the
programming of bespoke software.
Project
Management
The development and installation of a particular IS/IT
project is outsourced. For example, a new accounting
system.
Partial
Some IT/IS services are outsourced. Examples include
hardware maintenance, network management or ongoing
website management.
Total
An external supplier provides the vast majority of an
organization’s IS/IT services; eg third party owns or is
responsible for IT equipment, software and staff.
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Advantage of Outsourcing
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Outsourcing can remove uncertainty about Cost, as there
is often a long-term contract where services are specified
in advance for a fixed price.
Long-term contracts encourage planning for the future.
Outsourcing can bring the benefits of economies of
scale. For example, a FM company may conduct
research into new technologies that benefits a number of
their clients.
A specialist organization is able to retain skills and
knowledge. Many organizations would not have a
sufficiently well-developed IT department to offer IT
staff opportunities for career development. Talented staff
would leave to pursue their careers elsewhere.
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New skills and knowledge become available. A specialist
company can share staff with specific expertise between
several clients. This allows the outsourcing company to
take advantage of new developments without the need to
recruit new people or re-train existing staff, and without
the cost.
Flexibility (contracting permitting). Resources may be
able to be scaled up or down depending upon demand. For
instance, during a major changeover form one system to
another the number of IT staff needed may be twice as
large as it will be once the new system is working
satisfactorily.
An outsourcing organization is more able to arrange its
work on a project basis, whereby some staff will expect to
be moved periodically from one project to the next.
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Disadvantages of outsourcing
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It is arguable that information and its provision is an
inherent part of the business and of management. Unlike
office cleaning, or catering, an organization’s IT services
may be too important to be contracted out. Information
is at the heart of management.
A company may have highly confidential information
and to let outsiders handle it could be seen as risky in
commercial and/or legal terms.
If a third party is handling IS/IT services there is no onus
upon internal management to keep up with new
development or to suggest new ideas. Consequently,
opportunities to gain competitive advantage may be
missed. Any new technology or application devised by
the third party is likely to be available to competitors.
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An organization may find itself locked in to an
unsatisfactory contract. The decision may be very difficult
to reverse. If the service provider supplies unsatisfactory
levels of service, the effort and expense the organization
would incur to rebuild its own computing function or to
move to another provider could be substantial.
The use of outside organization does not encourage
awareness of the potential costs and benefits of IS/IT
within the organization. If manager cannot manage inhouse IS/IT resources effectively, then it could be argued
that they will not be able to manage an arrangement to
outsource effectively either.